Substrate processing apparatus

ABSTRACT

A substrate processing apparatus processes a substrate such as a semiconductor wafer by supplying a processing liquid. The substrate processing apparatus includes a substrate holder ( 1 ) for holding and rotating a substrate (W), a lower surface processing unit ( 2 ) for processing a lower surface of the substrate (W) by supplying a processing liquid to the lower surface of the substrate (W), and an outer circumferential edge processing unit ( 3 ) for processing an outer circumferential edge of the substrate (W) by supplying the processing liquid to the outer circumferential edge of the substrate (W). The substrate processing apparatus further includes a gas supply unit ( 5 ) for supplying a gas to an upper surface of the substrate (W).

TECHNICAL FIELD

[0001] The present invention relates to a substrate processing apparatus, and more particularly to a substrate processing apparatus for supplying a given processing liquid to a substrate such as a semiconductor wafer, a glass substrate, or a liquid crystal panel to perform an etching process or other processes.

BACKGROUND ART

[0002] In a semiconductor fabricating process for fabricating semiconductor devices using substrates such as semiconductor wafers, the step of forming a thin film on a substrate is carried out. Such a thin film is produced by any of various processes including sputtering, CVD (Chemical Vapor Deposition), plating, and the like. In the case where the formation of a thin film on a substrate is performed using one of the above processes, the thin film is generally formed on the entire surfaces of the substrate. However, the thin film is practically required to be formed on one side of the substrate, in particular, a circuit-forming area of the substrate. The thin film applied to the entire surfaces of the substrate or the thin film applied to an area of the substrate where it is not necessary may possibly be transferred to another substrate through a hand of a transport robot when the substrate is transported, or may possibly be peeled off and scattered around, resulting in a so-called cross contamination in which the peeled-off thin film fragments contaminate the processing environments of other processes. In the semiconductor fabricating process, therefore, unnecessary thin film portions are removed from the substrate after the formation of the thin film.

[0003] One widely practiced method of removing such unnecessary thin film portions is an etching process for selectively removing the unwanted thin film from the substrate by supplying an etching liquid to the substrate. Specifically, the etching process removes the unwanted thin film by supplying an etching liquid serving as a processing liquid to the surface of the substrate which is being held by a gripping tool such as a chuck. The etching process is carried out by a substrate processing apparatus which generally comprises a substrate holder for holding the substrate by a chuck or the like, and a processing liquid supply unit for supplying the processing liquid to the substrate that is being held by the substrate holder.

[0004] In the case where the etching process is carried out using the above substrate processing apparatus, the following problems arise:

[0005] Since the substrate holder holds the substrate by gripping the substrate with the gripping tool such as a chuck, the area of the substrate which is contacted by the gripping tool is not supplied with the etching liquid, and hence the thin film remains unremoved from such area of the substrate. Therefore, it is necessary to grip another area of the substrate by the gripping tool again and perform the etching process again. As a result, the processing time required to remove the thin film from the substrate and the amount of the etching liquid which is applied to the substrate are increased.

[0006] A vacuum chuck-type holder for holding the substrate under vacuum by a vacuum pad or the like without using the gripping tool is employed. However, the vacuum chuck-type holder is disadvantageous in that the reverse side of the substrate cannot be etched because the reverse side of the substrate to be processed is attracted and held under vacuum.

[0007] Further, there is still another device referred to as a Bernoulli chuck-type holder which does not directly hold the substrate. With the Bernoulli chuck-type holder, it is difficult to control the boundary line between an area where the thin film is to be unremoved and an area where the thin film is to be removed, on the surface of the substrate on which the circuit-forming area is formed, particularly on an outer circumferential portion of the substrate.

[0008] According to another substrate processing apparatus, the reverse side of the substrate is etched by being rinsed with a chemical liquid. In this substrate processing apparatus, the substrate is required to be rotated at a certain high speed in order to spread the chemical liquid over the entire reverse side of the substrate. Thus, the applied chemical liquid is scattered around and attached to undesirable areas of the substrate, thus contaminating the substrate. Furthermore, in case of recovering and reutilizing the chemical liquid, because the scattered chemical liquid is liable to be attached to wall surfaces of apparatuses for carrying out other processes, the amount of the chemical liquid to be recovered is decreased.

DISCLOSURE OF INVENTION

[0009] It is therefore an object of the present invention to provide a substrate processing apparatus which can process all areas of a substrate that need to be processed within a short period of time, and can prevent a processing liquid from being applied to areas of the substrate that do not need to be processed.

[0010] In order to achieve the above object, according to the present invention, there is provided a substrate processing apparatus comprising: a substrate holder for holding and rotating a substrate; a lower surface processing unit for processing a lower surface of the substrate by supplying a processing liquid to the lower surface of the substrate held by the substrate holder; an outer circumferential edge processing unit for processing an outer circumferential edge of the substrate by supplying the processing liquid to an outer circumferential edge of the substrate held by the substrate holder; and a gas supply unit for supplying a gas to an upper surface of the substrate held by the substrate holder.

[0011] According to the present invention, the substrate processing apparatus can process not only the lower surface of the substrate, but also the outer circumferential edge of the substrate. Therefore, the substrate processing apparatus is capable of reliably processing an area of the substrate which needs to be processed. Furthermore, the gas is supplied to the upper surface of the substrate to prevent the processing liquid and a vapor of the processing liquid from being applied to the upper surface of the substrate. Consequently, the upper surface of the substrate which is not required to be processed is protected from the processing liquid.

[0012] The substrate processing apparatus further comprises a processing liquid supply unit for supplying the processing liquid to the lower surface processing unit and the outer circumferential edge processing unit.

[0013] In a preferred aspect of the present invention, the substrate holder comprises a plurality of rotating rollers for contacting an outer circumferential surface of the substrate, and an actuator for rotating at least one of the rotating rollers. Inasmuch as the substrate is held by the rotating rollers and rotated about its own axis, the regions of the substrate which are held by the rotating rollers move at all times. Therefore, the processing liquid can be supplied to the regions of the substrate which are held by the substrate holder without being obstructed by the substrate holder. Thus, it is not necessary to hold and process the substrate again, resulting in a reduction in the time required to process the substrate.

[0014] In a preferred aspect of the present invention, the lower surface processing unit comprises a first facing member having a flat surface facing the lower surface of the substrate held by the substrate holder, and a processing liquid passage formed in said first facing member so as to be open at the flat surface of the first facing member. The processing liquid is supplied through the processing liquid passage to the flat surface of the first facing member. The processing liquid supplied to the flat surface is spread on the entire lower surface of the substrate while being held in contact with the lower surface of the substrate under surface tension. Therefore, it is not necessary to rotate the substrate at a high rotational speed for the purpose of spreading the processing liquid on the entire lower surface of the substrate. The processing liquid is thus prevented from being scattered around by the rotating substrate, and can be recovered at a high rate.

[0015] In a preferred aspect of the present invention, the outer circumferential edge processing unit is movable toward and away from the substrate held by the substrate holder. More preferably, the outer circumferential edge processing unit comprises a rotatable processing roller having a groove defined in an outer circumferential surface thereof for surrounding the outer circumferential edge of the substrate held by the substrate holder.

[0016] When the outer circumferential edge processing unit is moved closely to or into contact with the substrate, the processing liquid supplied to the first facing member of the lower surface processing unit is delivered via the first facing member and the substrate to the outer circumferential edge processing unit, and is then supplied through the groove in the processing roller to the outer circumferential edge of the substrate, whereby the outer circumferential edge of the substrate is processed. That is, the processing liquid which is led to the processing roller is retained by the groove in the processing roller and is then supplied to the entire circumference of the outer circumferential edge of the substrate by the rotation of the substrate. Thus, the outer circumferential edge of the substrate is processed. In this manner, since the lower surface and outer circumferential edge of the substrate can be simultaneously processed with the processing liquid which is supplied to the lower surface processing unit, the amount of the processing liquid used can be reduced, and the time required to process the substrate can be shortened. The processing roller may be adjusted in position with respect to the substrate to establish exactly an area of the substrate which is to be processed and an area of the substrate which is not to be processed on the outer circumferential edge of the substrate.

[0017] In a preferred aspect of the present invention, the gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by the substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by the substrate holder and a lower surface of the second facing member.

[0018] When the processing liquid supplied from the lower surface processing unit and the outer circumferential edge processing unit attempts to enter the upper surface of the substrate, the processing liquid is pushed back by the gas supplied from the gas supply unit. Therefore, the processing liquid is prevented from being supplied to the upper surface of the substrate which is not required to be processed. If the gas comprises a nitrogen gas, then the space defined between the upper surface of the substrate and the lower surface of the second facing member can be filled with the nitrogen gas, and the nitrogen gas functions as a purging gas for protecting the upper surface of the substrate from a vapor of the processing liquid.

[0019] The above and other objects, features, and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate a preferred embodiment of the present invention by way of example.

BRIEF DESCRIPTION OF DRAWINGS

[0020]FIG. 1 is a cross-sectional view, partly in block form, of a substrate processing apparatus according to an embodiment of the present invention;

[0021]FIG. 2 is a plan view of the substrate processing apparatus according to the embodiment of the present invention;

[0022]FIG. 3A is an enlarged elevational view of a processing unit for processing an outer circumferential edge in the substrate processing apparatus according to the embodiment of the present invention;

[0023]FIG. 3B is an enlarged fragmentary view of an outer circumferential edge of a substrate processed by the substrate processing apparatus according to the embodiment of the present invention; and

[0024]FIG. 4 is a plan view of a substrate processing system which incorporates the substrate processing apparatus according to the embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0025] A substrate processing apparatus according to an embodiment of the present invention will be described with reference to drawings.

[0026] As shown in FIG. 1, a substrate processing apparatus according to the present invention has a substrate holder 1 for holding a substrate W, a lower surface processing unit 2 for processing the lower surface of the substrate W by supplying a processing liquid to the lower surface of the substrate W, and a pair of outer circumferential edge processing units 3 for processing the outer circumferential edge of the substrate W by supplying a processing liquid to the outer circumferential edge of the substrate W. The substrate processing apparatus further comprises a processing liquid supply unit 4 for supplying a processing liquid to the lower surface processing unit 2 and the outer circumferential edge processing units 3, a gas supply unit 5 for supplying a gas to the upper surface of the substrate W, and a processing liquid recovery unit 6 for recovering the processing liquid which has been used to process the substrate W and supplying the recovered processing liquid to the processing liquid supply unit 4.

[0027] As shown in FIG. 2, the substrate holder 1 has four rotating rollers 11 for holding the substrate W and rotating the substrate W in a horizontal plane. The rotating rollers 11 are rotatable about their own axes by respective motors (not shown). The rotating rollers 11 are movable so as to be brought into contact with or out of contact with the substrate W in the directions indicated by the arrows. When the substrate W is loaded in the substrate processing apparatus, the four rotating rollers 11 are moved toward the substrate W and contact the outer circumferential surface of the substrate W. The substrate W is held in position by the rotating rollers 11 which contact or engage the outer circumferential surface thereof. When the rotating rollers 11 are rotated about their own axes by the corresponding motors, the substrate W held by the rotating rollers 11 is rotated about its own axis. In this case, the rotating rollers 11 may be rotated by the respective motors couple to the rotating rollers 11 or may be rotated by at least one motor coupled to one of the rotating rollers 11. The rotational speed of the rotating rollers 11 is set to a preset value so that the substrate W is rotated at a rotational speed in the range of 5 to 100 rpm (min⁻¹). In the illustrated embodiment, the substrate W is held by the substrate holder 1 in such a manner that the surface of the substrate W which needs to be processed by the processing liquid faces downwardly, and the surface of the substrate W which does not need to be processed by the processing liquid, e.g. the surface with a circuit-forming area thereon, faces upwardly.

[0028] As shown in FIG. 1, the lower surface processing unit 2 has a first facing member 14 having a flat surface 14 a which faces the lower surface of the substrate W held by the substrate holder 1. The lower surface processing unit 2 also has a processing liquid passage 15 having one end open substantially centrally in the flat surface 14 a of the first facing member 14 and the other end connected to the processing liquid supply unit 4. With this arrangement, the processing liquid supplied from the processing liquid supply unit 4 is supplied through the vertical processing liquid passage 15 to the upper surface of the first facing member 14, i.e. the flat surface 14 a.

[0029] The first facing member 14 is vertically movable by an actuator (not shown) and can move to a position close to the lower surface of the substrate W held by the substrate holder 1, this position of the first facing member 14 being spaced from the lower surface of the substrate W by a distance of 0.5 to 4 mm. Therefore, when the first facing member 14 is lifted, a small gap is created between the flat surface 14 a (upper surface) of the first facing member 14 and the lower surface of the substrate W. The processing liquid supplied from the processing liquid passage 15 to the flat surface 14 a of the first facing member 14 fills the small gap, and hence is supplied to the lower surface of the substrate W.

[0030] The lower surface processing unit 2 also has a pure water supply passage 21 extending parallel to the processing liquid passage 15. The pure water supply passage 21 has one end open substantially centrally in the flat surface 14 a of the first facing member 14 and the other end connected to a pure water supply source (not shown). With this arrangement, pure water supplied from the pure water supply source is supplied in the direction indicated by the arrow A of FIG. 1 to a pipe 18 e, and is then supplied through the pure water supply passage 21 to the flat surface 14 a of the first facing member 14. The substrate processing apparatus has a receptacle-like wall 50, and a first pure water ejecting device 22 for ejecting pure water to the upper surface of the substrate W held by the substrate holder 1 is provided on an inner wall surface of the wall 50.

[0031] The processing liquid supply unit 4 comprises a processing liquid container 16, a heating device 20, a pump 17, and a filter 19 which are interconnected by a pipe 18 c. The processing liquid which is stored in the processing liquid container 16 is delivered by the pump 17 through the pipe 18 c to the filter 19, and impurities are removed from the processing liquid by the filter 19. The processing liquid is then delivered from the filter 19 to the heating device 20 connected to the processing liquid passage 15 by a pipe 18 d. The processing liquid delivered to the heating device 20 is heated to a certain temperature by the heating device 20, and then supplied through the pipe 18 d to the processing liquid passage 15.

[0032] A first directional control valve 37 is provided in the pipe 18 d which connects the heating device 20 and the processing liquid passage 15. By switching the first directional control valve 37, the processing liquid is supplied to the pipe 18 b, rather than the processing liquid passage 15. The pipe 18 b is connected to the processing liquid container 16, thus making up a heated circulation path for the processing liquid to circulate through the processing liquid container 16, the heating device 20, and the filter 19. The pump 17, the pipes 18 b, 18 c and 18 d, and the first directional control valve 37 function as a circulating device for circulating the processing liquid between the processing liquid container 16 and the heating device 20.

[0033] As shown in FIG. 3A, each of the outer circumferential edge processing units 3 has a processing roller 25 and a base 27 supporting the processing roller 25 rotatably on its upper end. The processing roller 25 has an annular groove 26 defined in an outer circumferential surface thereof. The groove 26 has a rectangular cross section so as to surround the outer circumferential edge of the substrate W. The groove 26 has a depth of about 10 mm, and is positioned such that when the processing roller 25 is moved closely to the substrate W held by the substrate holder 1, the outer circumferential edge of the substrate W enters the groove 26. The processing roller 25 is made of any of various materials including synthetic resin, nonwoven fabric, porous synthetic resin, and the like. The outer circumferential edge of the substrate W is defined as upper and lower surfaces of the substrate W in the vicinity of the outer circumference thereof and an outer circumferential surface of the substrate W which faces radially outwardly, as indicated by C in FIG. 3B. An area D of the substrate W is an area that does not need to be processed by the processing liquid.

[0034] A reversible pulse-controlled motor 28 is housed in the base 27 and mounted on the bottom of the base 27. A male screw member 29 is connected at an end thereof to the drive shaft of the pulse-controlled motor 28. The male screw member 29 is threaded in a female screw member (not shown) fixed to the inner wall surface of the substrate processing apparatus. With this arrangement, when the pulse-controlled motor 28 is energized, since the male screw member 29 is threaded in the female screw member fixed to the inner wall surface of the substrate processing apparatus, the outer circumferential edge processing unit 3 housing the pulse-controlled motor 28 therein changes its position. Therefore, when the pulse-controlled motor 28 is energized, the processing roller 25 can be moved horizontally toward or away from the substrate W. The processing roller 25 can thus be adjusted in position with respect to the substrate W to establish exactly the boundary line of an area of the substrate W which is to be processed. As shown in FIG. 3A, the boundary line at the outer circumferential edge of the substrate W which is processed by the outer circumferential edge processing unit 3 can be adjusted with such depth d that the substrate W enters the groove 26. As shown in FIG. 1, second pure water ejecting devices 23 for ejecting pure water to the processing rollers 25 of the outer circumferential edge processing units 3 are mounted on the inner wall surface of the substrate processing apparatus.

[0035] The gas supply unit 5 has a second facing member 31 which is circular in shape and lies substantially horizontally in confronting relation to the upper surface of the substrate W held by the substrate holder 1. The second facing member 31 has a diameter which is slightly smaller than the diameter of the substrate W, as shown in FIG. 2. The gas supply unit 5 has a gas passage 32 having one end open at the lower surface of the second facing member 31 near the outer circumferential edge thereof, and the other end connected to a gas supply source (not shown).

[0036] The gas passage 32 and the gas supply source function as a gas supply means for supplying a gas into a space that is defined between the upper surface of the substrate W held by the substrate holder 1 and the lower surface of the second facing member 31. Specifically, a certain gas supplied from the gas supply source is supplied in the direction indicated by the arrow B into the gas passage 32, passes through the gas passage 32, and is then supplied from the position close to the outer circumferential edge of the second facing member 31 to the substrate W. The second facing member 31 is vertically movable by an actuator (not shown) and can move to a position close to the upper surface of the substrate W held by the substrate holder 1, this position of the second facing member 31 being spaced from the upper surface of the substrate W by a distance of 0.5 to 5 mm.

[0037] The processing liquid recovery unit 6 has a plurality of inclined recovery plates 35 disposed below the first facing member 14 for recovering the processing liquid falling off the first facing member 14, and a gas-liquid separator 36 for separating the processing liquid recovered by the inclined recovery plates 35 from a gas. The inclined recovery plates 35 and the gas-liquid separator 36 are connected to each other by pipes 18 a. The gas-liquid separator 36 is connected to the processing liquid container 16 through a second directional control valve 38 and the pipe 18 b. With this arrangement, the processing liquid which has processed the substrate W is recovered by the inclined recovery plates 35 and delivered therefrom to the gas-liquid separator 36. The processing liquid is separated from a gas by the gas-liquid separator 36, and then delivered to the processing liquid container 16. The gas separated by the gas-liquid separator 36 is discharged from a gas discharge port 39.

[0038] The second directional control valve 38 has a drain port 40, and by switching the second directional control valve 38, the liquid discharged from the gas-liquid separator 36 is discharged from the drain port 40, rather than delivered to the processing liquid container 16. Specifically, when the substrate W is cleaned by pure water supplied from the pure water supply passage 21, the second directional control valve 38 is operated to discharge the pure water from the drain port 40 without delivering the pure water to the processing liquid container 16.

[0039] If the temperature of the processing liquid recovered by the processing liquid recovery unit 6 is low, the first directional control valve 37 may be operated to circulate the recovered processing liquid within the heated circulation path through the heating device 20 for thereby heating the processing liquid to a desired temperature.

[0040] Operation of the substrate processing apparatus thus constructed will be described below.

[0041] When the substrate W to be processed is loaded into the substrate processing apparatus by a transport robot or the like, the four rotating rollers 11 of the substrate holder 1 are moved toward the substrate W and brought into contact with the outer circumferential surface of the substrate W, thus holding the substrate W in position. When the substrate W is held by the rotating rollers 11, the first facing member 14 of the processing liquid supply unit 4 is lifted and then stopped in a position where the lower surface of the substrate W is spaced from the flat surface 14 a of the first facing member 14 by a distance ranging from 0.5 to 4 mm. At the same time that the first facing member 14 is lifted, the second facing member 31 of the gas supply unit 5 is lowered and then stopped in a position where the upper surface of the substrate W is spaced from the lower surface of the second facing member 31 by a distance ranging from 0.5 to 5 mm. Then, a nitrogen gas is ejected from the gas passage 32 to the upper surface of the substrate W.

[0042] Then, the rotating rollers 11 are rotated by the respective motors to rotate the substrate W at a rotational speed ranging from 5 to 100 rpm (min⁻¹). When the substrate W is rotated, the processing liquid is delivered from the processing liquid container 16 to the heating device 20 by the pump 17, and then heated to a given temperature by the heating device 20. Thereafter, the heated processing liquid is supplied through the processing liquid passage 15 to the substantially central area of the flat surface 14 a of the first facing member 14. The processing liquid supplied to the flat surface 14 a of the first facing member 14 starts to fill up the gap between the first facing member 14 and the substrate W, and hence starts to be supplied to the lower surface of the substrate W. At the same time that the processing liquid is supplied to the lower surface of the substrate W, the processing rollers 25 are moved toward the substrate W by the pulse-controlled motors 28. The processing rollers 25 are stopped when the outer circumferential edge of the substrate W enters the grooves 26 in the processing rollers 25 and reaches a given position in the grooves 26. The position where the processing rollers 25 are to be stopped may be preset to define in advance an area to be processed on the outer circumferential edge of the substrate W.

[0043] The processing liquid supplied from the substantially central area of the first facing member 14 is spread radially outwardly under centrifugal forces by the rotating substrate W through the gap between the substrate W and the first facing member 14. The processing liquid is thus supplied to the entire lower surface of the substrate W. When the processing liquid spreading on the lower surface of the substrate W reaches the processing rollers 25, the processing liquid enters a small gap between the roller 25 and the substrate W as indicated by the arrow E of FIG. 3A, thereby processing the outer circumferential edge of the substrate W. That is, the processing liquid which is led to the processing roller 25 is retained by the groove 26 in the processing roller 25 and is then supplied to the entire circumference of the outer circumferential edge of the substrate W by the rotation of the substrate W. Thus, the outer circumferential edge of the substrate W is processed. The outer circumferential edge of the substrate W is processed by the processing liquid at a region from the outer circumferential surface to a radially inner portion by the distance “d”. At this time, a portion of the processing liquid tends to enter the area D of the substrate W which does not need to be processed. However, because the processing liquid is pushed back by the nitrogen gas supplied from the lower surface of the second facing member 31, the processing liquid is prevented from entering the area D of the substrate W.

[0044] The processing liquid which has been supplied to the lower surface and outer circumferential edge of the substrate W and has processed the substrate then drops off the substrate W and flows down the inclined recovery plates 35 into the gas-liquid separator 36. In the gas-liquid separator 36, the processing liquid is separated from a gas, and the gas is discharged from the gas discharge port 39 and the processing liquid is supplied through the pipe 18 b to the processing liquid container 16.

[0045] After the substrate W has been processed for a predetermined period of time, the processing rollers 25 are displaced away from the substrate W, and the pump 17 is turned off to stop the supply of the processing liquid. Then, the first facing member 14 is lowered, and simultaneously the second facing member 31 is elevated. Thereafter, pure water is supplied from the pure water supply passage 21 and the first pure water ejecting device 22 to the substrate W to remove the processing liquid which remains on the upper and lower surfaces of the substrate W. Pure water is also ejected from the second pure water ejecting devices 23 to remove the processing liquid attached to the processing rollers 25. At this time, the second directional control valve 38 has been operated to connect the gas-liquid separator 36 to the drain port 40. Therefore, the pure water which has cleaned the substrate W and the processing rollers 25 is recovered by the inclined recovery plates 35, passes through the gas-liquid separator 36, and is then discharged from the drain port 40. Thereafter, the rotation of the substrate W is stopped, and the substrate W is then unloaded from the substrate processing apparatus by the transport robot. The processing sequence of the substrate processing apparatus is now finished.

[0046] The substrate processing apparatus according to the present invention can process the substrate W in a short period of time because it can process the lower surface of the substrate W and the outer circumferential edge thereof at the same time. Since the processing liquid can be supplied to the regions where the rotating rollers 11 and the substrate W contact each other, it is not necessary to hold the substrate W again and process the substrate W again, resulting in a reduction in the processing time. In as much as the nitrogen gas is supplied to protect the upper surface of the substrate W, the upper surface of the substrate W which does not need to be processed is prevented from being processed. Furthermore, because the substrate W is rotated at a relatively low rotational speed ranging from 5 to 100 rpm (min⁻¹), the processing liquid applied to the substrate W is not scattered around, and can be recovered at a relatively high rate.

[0047] A substrate processing system which incorporates the substrate processing apparatus according to the present invention will be described below. In the substrate processing system, the substrate processing apparatus processes a semiconductor wafer (hereinafter referred to as “wafer”) with a thin film formed thereon by etching the wafer with an etching liquid. However, the present invention is not limited to such a substrate processing apparatus.

[0048]FIG. 4 shows in plan a substrate processing system which incorporates the substrate processing apparatus according to the present invention. As shown in FIG. 4, the substrate processing system has two wafer cassettes 51 a, 51 b each for storing a plurality of wafers W, a substrate processing apparatus 52 for etching a wafer W, a substrate cleaning apparatus 53 for cleaning the wafer W which has been etched, and a substrate drying apparatus 54 for drying the wafer W which has been dried. The substrate processing system also has a first transport robot 55 a and a second transport robot 55 b for transporting wafers W between the above apparatuses, and a transport buffer stage 56 for temporarily placing a wafer (or wafers) W to transfer the wafer W between the transport robots 55 a and 55 b.

[0049] Each of the wafer cassettes 51 a, 51 b has a plurality of storage shelves (not shown) for storing respective wafers W. A wafer W is removed from either one of the wafer cassettes 51 a, 51 b by the first transport robot 55 a, and then transferred via the transport buffer stage 56 to the second transport robot 55 b. The wafer W transferred to the second transport robot 55 b is introduced into the substrate processing apparatus 52 in which the wafer W is etched. The substrate processing apparatus 52 is of the same structure and operates in the same manner as the substrate processing apparatus described above with reference to FIGS. 1 through 3A and 3B. If a film of copper attached to or deposited on the wafer W is to be etched, then the etching liquid used in the substrate processing apparatus 52 comprises a combination of an acid solution and an oxidizing agent solution, for example, which are simultaneously or alternately supplied to etch the film of copper. The acid solution may be a solution containing a non-oxidizing acid, e.g., hydrofluoric acid, hydrochloric acid, sulfuric acid, citric acid, oxalic acid, or the like. The oxidizing agent solution may be ozone water, hydrogen peroxide water, nitric acid water, sodium hypochlorite water, or the like.

[0050] After having been etched in the substrate processing apparatus 52, the wafer W is introduced into the substrate cleaning apparatus 53 by the second transport robot 55 b. The substrate cleaning apparatus 53 has a sponge roll (not shown) supplied with a cleaning liquid, and cleans the wafer W by bringing the sponge roll in contact with the wafer W while holding and rotating the wafer W. Products that have been produced by the etching process are removed from the wafer W by the substrate cleaning apparatus 53. The cleaned wafer W is then transported from the substrate cleaning apparatus 53 to the substrate drying apparatus 54 by the second transport robot 55 b. The substrate drying apparatus 54 has a spin drier (not shown) for drying the wafer W by spinning the wafer W at a high rotational speed. The spin drier dries the cleaning liquid attached to the wafer W. The dried wafer W is transported by the first transport robot 55 a and placed into one of the wafer cassettes 51 a, 51 b. The processing sequence of the substrate processing system is now finished. The substrate processing apparatus according to the present invention can thus be incorporated in the substrate processing system which carries out various processes including the etching process, the cleaning process, and the drying process.

[0051] According to the present invention, the substrate processing apparatus can process the substrate W in a short period of time because it can process the lower surface of the substrate and the outer circumferential edge thereof at the same time. Inasmuch as a gas is supplied to protect the upper surface of the substrate, the processing liquid and a vapor of the processing liquid are prevented from being applied to upper surface of the substrate which does not need to be processed.

[0052] Because the substrate is held by the rotating rollers, the regions where the rotating rollers and the substrate contact each other move at all times, thus allowing the processing liquid to be supplied to those contact regions. Consequently, it is not necessary to hold the substrate again and process the substrate again, resulting in a reduction in the processing time. Furthermore, because the substrate is rotated at a relatively low rotational speed, the processing liquid applied to the substrate is not scattered around, and can be recovered at a relatively high rate.

[0053] Although a certain preferred embodiment of the present invention has been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.

Industrial Applicability

[0054] The present invention is applicable to a substrate processing apparatus for supplying a given processing liquid to a substrate such as a semiconductor wafer, a glass substrate, or a liquid crystal panel to perform an etching process or other processes. 

1. A substrate processing apparatus comprising: a substrate holder for holding and rotating a substrate; a lower surface processing unit for processing a lower surface of the substrate by supplying a processing liquid to the lower surface of the substrate held by said substrate holder; an outer circumferential edge processing unit for processing an outer circumferential edge of the substrate by supplying the processing liquid to an outer circumferential edge of the substrate held by said substrate holder; and a gas supply unit for supplying a gas to an upper surface of the substrate held by said substrate holder.
 2. A substrate processing apparatus according to claim 1, further comprising: a processing liquid supply unit for supplying the processing liquid to said lower surface processing unit and said outer circumferential edge processing unit.
 3. A substrate processing apparatus according to claim 1, wherein said substrate holder comprises a plurality of rotating rollers for contacting an outer circumferential surface of the substrate, and an actuator for rotating at least one of said rotating rollers.
 4. A substrate processing apparatus according to claim 1, wherein said lower surface processing unit comprises a first facing member having a flat surface facing the lower surface of the substrate held by said substrate holder, and a processing liquid passage formed in said first facing member so as to be open at said flat surface of said first facing member.
 5. A substrate processing apparatus according to claim 4, wherein said first facing member and the substrate held by said substrate holder are spaced from each other by a distance ranging from 0.5 to 4 mm.
 6. A substrate processing apparatus according to claim 1, wherein said outer circumferential edge processing unit is movable toward and away from the substrate held by said substrate holder.
 7. A substrate processing apparatus according to claim 1, wherein said outer circumferential edge processing unit comprises a rotatable processing roller having a groove defined in an outer circumferential surface thereof for surrounding the outer circumferential edge of the substrate held by said substrate holder.
 8. A substrate processing apparatus according to claim 2, wherein said processing liquid supply unit comprises a processing liquid container for storing the processing liquid therein, a heating device for heating the processing liquid supplied from said processing liquid container, and a circulating device for circulating the processing liquid between said processing liquid container and said heating device.
 9. A substrate processing apparatus according to claim 1, wherein said gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by said substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by said substrate holder and a lower surface of said second facing member.
 10. A substrate processing apparatus according to claim 9, wherein said second facing member is circular in shape and has a diameter smaller than the diameter of said substrate.
 11. A substrate processing apparatus according to claim 9, wherein said second facing member and the substrate held by said substrate holder are spaced from each other by a distance ranging from 0.5 to 5 mm.
 12. A substrate processing apparatus according claim 2, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 13. A substrate processing apparatus according to claim 1, wherein said processing liquid comprises an etching liquid.
 14. A substrate processing apparatus according to claim 2, wherein said substrate holder comprises a plurality of rotating rollers for contacting an outer circumferential surface of the substrate, and an actuator for rotating at least one of said rotating rollers.
 15. A substrate processing apparatus according to claim 2, wherein said lower surface processing unit comprises a first facing member having a flat surface facing the lower surface of the substrate held by said substrate holder, and a processing liquid passage formed in said first facing member so as to be open at said flat surface of said first facing member.
 16. A substrate processing apparatus according to claim 3, wherein said lower surface processing unit comprises a first facing member having a flat surface facing the lower surface of the substrate held by said substrate holder, and a processing liquid passage formed in said first facing member so as to be open at said flat surface of said first facing member.
 17. A substrate processing apparatus according claim 2, wherein said outer circumferential edge processing unit is movable toward and away from the substrate held by said substrate holder.
 18. A substrate processing apparatus according claim 3, wherein said outer circumferential edge processing unit is movable toward and away from the substrate held by said substrate holder.
 19. A substrate processing apparatus according claim 4, wherein said outer circumferential edge processing unit is movable toward and away from the substrate held by said substrate holder.
 20. A substrate processing apparatus according claim 5, wherein said outer circumferential edge processing unit is movable toward and away from the substrate held by said substrate holder.
 21. A substrate processing apparatus according to claim 2, wherein said outer circumferential edge processing unit comprises a rotatable processing roller having a groove defined in an outer circumferential surface thereof for surrounding the outer circumferential edge of the substrate held by said substrate holder.
 22. A substrate processing apparatus according to claim 3, wherein said outer circumferential edge processing unit comprises a rotatable processing roller having a groove defined in an outer circumferential surface thereof for surrounding the outer circumferential edge of the substrate held by said substrate holder.
 23. A substrate processing apparatus according to claim 4, wherein said outer circumferential edge processing unit comprises a rotatable processing roller having a groove defined in an outer circumferential surface thereof for surrounding the outer circumferential edge of the substrate held by said substrate holder.
 24. A substrate processing apparatus according to claim 5, wherein said outer circumferential edge processing unit comprises a rotatable processing roller having a groove defined in an outer circumferential surface thereof for surrounding the outer circumferential edge of the substrate held by said substrate holder.
 25. A substrate processing apparatus according to claim 6, wherein said outer circumferential edge processing unit comprises a rotatable processing roller having a groove defined in an outer circumferential surface thereof for surrounding the outer circumferential edge of the substrate held by said substrate holder.
 26. A substrate processing apparatus according to claim 3, wherein said processing liquid supply unit comprises a processing liquid container for storing the processing liquid therein, a heating device for heating the processing liquid supplied from said processing liquid container, and a circulating device for circulating the processing liquid between said processing liquid container and said heating device.
 27. A substrate processing apparatus according to claim 4, wherein said processing liquid supply unit comprises a processing liquid container for storing the processing liquid therein, a heating device for heating the processing liquid supplied from said processing liquid container, and a circulating device for circulating the processing liquid between said processing liquid container and said heating device.
 28. A substrate processing apparatus according to claim 5, wherein said processing liquid supply unit comprises a processing liquid container for storing the processing liquid therein, a heating device for heating the processing liquid supplied from said processing liquid container, and a circulating device for circulating the processing liquid between said processing liquid container and said heating device.
 29. A substrate processing apparatus according to claim 6, wherein said processing liquid supply unit comprises a processing liquid container for storing the processing liquid therein, a heating device for heating the processing liquid supplied from said processing liquid container, and a circulating device for circulating the processing liquid between said processing liquid container and said heating device.
 30. A substrate processing apparatus according to claim 7, wherein said processing liquid supply unit comprises a processing liquid container for storing the processing liquid therein, a heating device for heating the processing liquid supplied from said processing liquid container, and a circulating device for circulating the processing liquid between said processing liquid container and said heating device.
 31. A substrate processing apparatus according to claim 2, wherein said gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by said substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by said substrate holder and a lower surface of said second facing member.
 32. A substrate processing apparatus according to claim 3, wherein said gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by said substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by said substrate holder and a lower surface of said second facing member.
 33. A substrate processing apparatus according to claim 4, wherein said gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by said substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by said substrate holder and a lower surface of said second facing member.
 34. A substrate processing apparatus according to claim 5, wherein said gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by said substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by said substrate holder and a lower surface of said second facing member.
 35. A substrate processing apparatus according to claim 6, wherein said gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by said substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by said substrate holder and a lower surface of said second facing member.
 36. A substrate processing apparatus according to claim 7, wherein said gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by said substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by said substrate holder and a lower surface of said second facing member.
 37. A substrate processing apparatus according to claim 8, wherein said gas supply unit comprises a second facing member disposed so as to face the upper surface of the substrate held by said substrate holder, and a gas supply device for supplying the gas into a space defined between the substrate held by said substrate holder and a lower surface of said second facing member.
 38. A substrate processing apparatus according to claim 10, wherein said second facing member and the substrate held by said substrate holder are spaced from each other by a distance ranging from 0.5 to 5 mm.
 39. A substrate processing apparatus according claim 3, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 40. A substrate processing apparatus according claim 4, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 41. A substrate processing apparatus according claim 5, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 42. A substrate processing apparatus according claim 6, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 43. A substrate processing apparatus according claim 7, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 44. A substrate processing apparatus according claim 8, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 45. A substrate processing apparatus according claim 9, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 46. A substrate processing apparatus according claim 10, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit.
 47. A substrate processing apparatus according claim 11, further comprising: a processing liquid recovery unit for recovering the processing liquid which has been supplied to said lower surface processing unit and said outer circumferential edge processing unit, and supplying the recovered processing liquid to said processing liquid supply unit. 